This is a note to let you know that I've just added the patch titled powerpc/perf: Fix PMU constraint check for EBB events to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-perf-fix-pmu-constraint-check-for-ebb-events.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 30b90ef693124861b53e3a941aa5b50cb2d933fc Author: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx> Date: Tue Apr 6 12:16:01 2021 -0400 powerpc/perf: Fix PMU constraint check for EBB events [ Upstream commit 10f8f96179ecc7f69c927f6d231f6d02736cea83 ] The power PMU group constraints includes check for EBB events to make sure all events in a group must agree on EBB. This will prevent scheduling EBB and non-EBB events together. But in the existing check, settings for constraint mask and value is interchanged. Patch fixes the same. Before the patch, PMU selftest "cpu_event_pinned_vs_ebb_test" fails with below in dmesg logs. This happens because EBB event gets enabled along with a non-EBB cpu event. [35600.453346] cpu_event_pinne[41326]: illegal instruction (4) at 10004a18 nip 10004a18 lr 100049f8 code 1 in cpu_event_pinned_vs_ebb_test[10000000+10000] Test results after the patch: $ ./pmu/ebb/cpu_event_pinned_vs_ebb_test test: cpu_event_pinned_vs_ebb tags: git_version:v5.12-rc5-93-gf28c3125acd3-dirty Binding to cpu 8 EBB Handler is at 0x100050c8 read error on event 0x7fffe6bd4040! PM_RUN_INST_CMPL: result 9872 running/enabled 37930432 success: cpu_event_pinned_vs_ebb This bug was hidden by other logic until commit 1908dc911792 (perf: Tweak perf_event_attr::exclusive semantics). Fixes: 4df489991182 ("powerpc/perf: Add power8 EBB support") Reported-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx> Signed-off-by: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx> [mpe: Mention commit 1908dc911792] Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/1617725761-1464-1-git-send-email-atrajeev@xxxxxxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c index e1a21d34c6e4..5e8eedda45d3 100644 --- a/arch/powerpc/perf/isa207-common.c +++ b/arch/powerpc/perf/isa207-common.c @@ -400,8 +400,8 @@ ebb_bhrb: * EBB events are pinned & exclusive, so this should never actually * hit, but we leave it as a fallback in case. */ - mask |= CNST_EBB_VAL(ebb); - value |= CNST_EBB_MASK; + mask |= CNST_EBB_MASK; + value |= CNST_EBB_VAL(ebb); *maskp = mask; *valp = value;